Impact scrubber

ABSTRACT

An impact scrubber for removing coating materials from the surfaces of particulate matter such as foundry sand and the like comprises a lift tube having an inlet end and an opposite end for containing a high velocity fluidized stream of said matter, fluid injector means spaced adjacent said inlet end for carrying said particulate matter into said inlet end and forming a fluidized stream of said matter in said lift tube, movable deflector means adjacent and in communication with said opposite end for directing said fluidized stream angularly outward with respect to a longitudinal axis of said lift tube for discharging said matter therefrom, support means for rotatively supporting said deflector means for directing said discharge therefrom in a selected one of a plurality of relative rotative positions, and means for separating the coating materials removed by impact from said particulate and said particulate matter.

Umted States Patent 1191 1111 3,907,213

Kauffman Sept. 23, 1975 IMPACT SCRUBBER [75] Inventor: John H. Kauffman,Richland Pnmary Examiner- Dlonald Kelly Center, Wis. Attorney, Agent, orFzrm-Mason, Koichmamen,

Rathburn & Wyss [73] Assignee'. National Engineering Company,

Chicago, Ill.

[57] ABSTRACT [22] Filed: May 2, 1974 An 1mpact scrubber for removingcoatmg materials PP 466,302 from the surfaces of particulate matter suchas foundry sand and the like comprises a lift tube having [52 U.S. c1241/40; 51/8 R; 241/1310. 10 an opposite FP f i "f high 51 1111.01.13020 19/06; B24C 3/00 veloclty flu1d1zed Stream 9 i a ter, fluid 11 6611 [58] Field 01 Search 51/8 R; 241/010. 10, 275, meaPs Spaced i end forCarrymg, particulate matter into sa1d inlet end and forming a241/102,5,39, 40, 42

flu1d1zed stream of said matter 1n said 11ft tube. mov- [56] ReferencesCited abi; dei'lgctor metans agjafcentdandtin comgiutrliiccziitiog 1 W1sa1 opposi e en 0r 1rec mg sai u1 ize LNITED TA PATENTS stream angularlyoutward with respect to a longitudi- 1,l27,615 2/1915 Gilligan 241/40 1axis f said ]ift t b f discharging said matter gerlnaldw 241/DIG- 1Otherefrom, support means for rotatively supporting u ver 241/40 UX saiddeflector means for directing said discharge 2,707,314 5/1955 Horth;24l/DIG. 10 h f I d f l f l 2,768,938 10/1956 Martin 241/40 x t mm "P Seecte one 0 a P 0 re 2,813,318 11/1957 Horth 241/1310. 10 Fomwe f meansseparatmg the coat- 2 939 9 6/1960 wenningeru 241/D]G 10 mg materialsremoved by impact from said particulate 3,062,459 11/1962 Dearing241/102 UX and i p r i la e m tter. 3,312,342 4/1967 Brown 241/40 x3,312,403 4/1967 Zifferer 241/010. 10 14 Clams 5 Drawmg Figures USPatent Sept. 23,1975 shw 1 of3 3,907,213

US Patent Sept. 23,1975 Sheet 3 of3 3,907,213

IMPACT SCRUBBER The present invention relates to a new and improvedimpact scrubber for removing coating materials from particulate matterand more particularly to new and improved apparatus for reclaiming forreuse the granular materials commonly used in foundry operations such asfoundry sand and the like. The present invention is an improvement overthe apparatus shown and described in copending patent application, Ser.No. 332,415 filed Feb. 14, 1973, now US. Pat. No. 3,825,190, inventedJuly 23, 1974, and assigned to the same assignee as the presentinvention.

In foundry operations granular base materials such as silica sand,zirconia sand and the like are coated with binding products, forexample, clays, cereals, resins, and oils and the resulting mixturecomprises foundry sand which is shaped and molded into definite shapesaround patterns to form mold cavities. Molten metal is poured into thecavities as castings are made. The molding sand is subjected to directcontact with hot molten metal and the binding products which coat thegranular sand base materials are oxidized and/or calcined in the moldingprocess by the intense heat involved. In order to recondition the basematerial for further use in subsequent foundry operations, it isdesirable to remove the oxidized coatings from the basic sand granulesand subsequently prepare the sand as molding sand in suitableformulations with the necessary binding products required for a mold.The oxidized or calcined coating materials on the used molding sandgranules are generally carbonaceous in nature and also are of agenerally lower density than the basic sand material itself.

Accordingly, it is desirable to provide a system for removing theencrusted coating material from the sand grains in a dry, mechanicalimpact scrubbing process and then separate the lighter weight coatingmaterials from the basic sand or particulater matter so that the cleansand may then be reused in subsequent molding operations afterreformulation with the necessary binders.

The impact scrubber of the present invention is a self-contained, highlyefficient unit, requiring a relatively small floor space, and isautomatically controlled to provide the desired scrubbing/cleaningaction as may be required for the particulate matter being treated.

It is an object of the present invention to provide a new and improvedimpact scrubber for treating particulate matter such as foundry sand andthe like, and

more particularly it is an object of the invention to provide a new andimproved scrubber of the character described which is highly efficientin operation, automatically controlled for operation and discharge andwhich requires a relatively small floor space per unit of capacity incomparison with prior sand scrubbers.

Another object of the present invention is to provide a new and improvedimpact scrubber for cleaning particulate matter having a plurality ofseparate impact type sand scrubbing units and means for controlling thedirection of discharge from all of said units simultaneously.

Another object is to provide a sand scrubber of the character describedincluding novel means for adjusting the application of the individualscrubbing units for the most efficient operation.

Another object of the present invention is to provide a new and improvedimpact scrubber for cleaning particulate matter having a novel targetsystem for receiving the impact of the fluidized flow of matter in orderto mechanically remove the calcined or oxidized coatings from theindividual particles of matter.

Another object of the invention is to provide a new and improved, dryprocess, mechanical impact type scrubber which includes a novel systemfor separating the coating materials from the grains of particulatematter.

Another object of the present invention is to provide a new and improvedimpact scrubber having a plurality of individual lift tube scrubberunits and means for automatically controlling thedirection of thedischarge of particulate matter for impact scrubbing or for dischargefrom the scrubber itself.

The foregoing and other objects and advantages of the present inventionare accomplished in an illustrated embodiment, by way of illustrationand not limitation, comprising a dry process, mechanical impact,scrubber for removing coating materials from the surfaces of particulatematter such as foundry sand and the like. The scrubber-comprises one ormore lift tubes, each having an inlet end and an opposite end forcontaining a high velocity fluidized stream of said matter and fluidinjector means spaced adjacent said inlet end for carrying saidparticulate matter into said inlet end and forming a fluidized stream insaid lift tube. Deflector means is provided adjacent and incommunication with the opposite ends of the lift tubes for directingsaid fluidized stream angularly outward with respect to the longitudinalaxes of said lift tubes for discharge therefrom. Support means isprovided for rotatively supporting said deflector means for directingsaid discharge therefrom in a selected one of a plurality of relativerotative positions. Means is provided for separating the coatingmaterials broken away from the grains of particulate matter and thecleaned grains of particulate matter so that the particulate matter maybe used again.

For a better understanding of the invention reference should be had tothe following detailed description taken in conjunction with thedrawings, in which;

FIG. I is an elevational view with portions shown in section of a newand improved impact scrubber for treating particulate matter constructedin accordance with the features of the present invention.

FIG. 2 is a transverse, horizontal cross sectional vie takensubstantially along lines 22 of FIG. 1;

FIG. 3 is another transverse horizontal cross sectional view takensubstantially along lines 22 of FIG. 1 but showing the scrubber units ina discharging position.

FIG. 4 is another transverse cross sectional view taken substantiallyalong lines 44 of FIG. 1; and

FIG. 5 is an enlarged fragmentary vertical sectional view takensubstantially along lines 55 of FIG. 4. 7

Referring now more particularly to the drawings therein is illustrated anew and improved impact scrubbing apparatus for the treatment ofparticulate matter such as foundry sand and the like and constructed inaccordance with the features of the present invention. The apparatus asa-whole is referred to by the reference numeral 10 and includes anupstanding cylindrical housing 12 having a circular base 14. At theupper end of the housing 12 there is provided a hopper 16 for holdingand receiving the sand or other particulate matter to be processed bythe scrubber. The hopper 16 includes a frustro-conical bottom wall 18having a circular shaped opening 20 at the lower end for feeding theparticulate matter downwardly into a cylindrical, intermediate sectionof the housing referred to by the numeral 22 and separated from an upperor hopper section of the housing by an annular wall 24. The intermediateor discharge section 22 of the housing is similarly separate from alower housing section 26 by an annular wall 28.

In accordance with the present invention, the scrubber 10 includes aplurality of vertically extending, impact type, lift tube scrubbingassemblies or units generally indicated by reference numeral 30. Asshown in FIG. 1, each scrubber unit extends upwardly from the lowerhousing section 26 through an opening in the annular wall 28 andprojects upwardly to the intermediate section 22 of the housing. In thelower housing section 26, the scrubber units 30 are disposed ondiametrically opposite sides of an upstanding, cylindrical, air plenumchamber 32 which is centrally positioned in the housing 12 and extendsbetween the circular bottom plate 14 and the circular wall 28. Theplenum chamber 32 is supplied with a high volume flow of pressurized airfrom a suitable source such as a Rootes" type blower or equivalent viaan inlet duct 34 which extends radially outwardly of the plenum chamberand passes through an appropriately shaped opening formed in the wall ofthe cylindrical housing 12.

Each of the lift tube scrubber units 30 includes a cylindrical outershell 36 having an annular mounting flange 38 adjacent the upper endsecured to the wall 28 in concentric relation with a circular openingtherein by suitable fasteners such as removable bolts 39. At the lowerend each shell 36 is provided with an annular lower end flange 40, whichflanges provide support for convergent type, high velocity, injectionnozzles 42 as shown in FIG. 1. Each nozzle 42 is removably attached toits supporting flange and is connected at its lower end via a coupling44 with a conduit structure in communication with the central plenumchamber 32 for receiving pressurized air. As illustrated, the conduitstructure includes an intermediate section 46 coupled at its lower endwith a control valve 48 which in turn is interconnected with the centralplenum chamber 32 by a supply elbow 50. The supply elbows radiateoutwardly from the plenum chamber and each elbow has a lower, horizontalleg 50a and a vertical leg 50b having its upper end connected to thelower end of a control valve 48.

In order to individually control and regulate the flow of pressurizedair from the central plenum chamber 32 to the nozzle 42 of eachscrubbing unit 30, the individual valves are adjusted and pressuregauges 52 connected to short pipe nipple sections 46 are provided forguiding the operator in adjustment of the valves to secure the desiredrate of flow of fluid through the nozzle. The central air plenum chamber32 provides a high volume source of pressurized air at relatively lowpressure (inches of water) for supplying the nozzles 42 of the lift tubescrubber units 30 and the valves 48 are utilized for individuallycontrolling the respective units in accordance with the pressure gaugereadings from the gauges 52.

After periods of inactivity of the scrubber l0, sand and other materialstend to collect in the lower end of the shells 36 and often tends toplug the nozzles 42 to such a degree the adequate air flow is preventedwhen the next start up is attempted. A high pressure compressed airstarting system is provided and this system includes an upstandingcompressed air injector 54 mounted in each elbow 50 and designed toinject high pressure (up to lOO psi) starting air into the materialcollected in elbows to clear the passage through the nozzles 42 and thelower end of the shells 36. The air injectors are connected to a commoncompressed air supply manifold 56 and a control valve 58 is provided.The manifold is connected to a suitable source of high pressure air.

Each cylindrical shell 36 is formed with an elongated, axially extendingaccess opening in the outer side wall thereof and these access openingsare sealed during operation by means of removable or hingedly attachedaccess doors 60. The doors permit servicing of the interior of theshells 36 and clean out of the units if required.

In accordance with the present invention, each lift tube unit 30includes an elongated, vertical lift tube 62 aligned in coaxialarrangement with an adjacent air supply nozzle 42 and spaced verticallyabove the outlet of the nozzle by an adjustable distance D. The lower orinlet end of each lift tube 62 is provided with a replaceable annularinlet ring 64 having a slightly tapered internal bore and the ring isadapted to receive and guide a fluidized flow of particulate matter intothe tube as it is entrained upwardly by the air jet issuing from thenozzle outlet. The high velocity air flow moving upwardly in the lifttubes forms a high velocity turbulent fluidized flow of particulatematter and air. During the entrainment of the particulate matter in theair jet adjacent the inlet end of the lift tube and during the upwardturbulent flow within the lift tube, intense interaction between theindividual particles of particulate matter takes place in the form ofrepeated random collisions. These collisions or impacts aid in breakingup and removing the encrusted coating materials on the sand grains andthis material along with the sand is carried upwardly in the turbulentstream.

The lift tubes 62 are adjusted in precise coaxial alignment with thenozzles 42 by means of radial spacers 66 mounted on the shells 36 andadjustable exteriorly thereof. The spacers are provided at upper andlower levels on the shells as shown and at each level a plurality ofspacers are provided (three or four) in order to permit precise axialalignment of the nozzle and lift tube.

The circular wall 28 is formed with circular openings 28a spacedradially outward of the center and in coaxial alignment with therespective shells 36 of the lift tube assemblies 30. These openings aresubstantially the same diameter as the internal diameter of the shells36 and the particulate matter from the chamber section 22 flowsdownwardly into the shells around the lift tubes 62 for pick up by theair jets issuing upwardly from the outlet of the nozzles 42.

The elongated side access openings in the shells 36 permit the lifttubes 62, nozzles 42 and inlet ring 64 to be serviced on replacedwithout complete dismantling of the scrubber units 30. The lower section26 of the housing 12 is provided with relatively large, vertical,elongated access openings or slots 68 which slots are large enough topermit easy insertion and withdrawal of the complete lift tube unit 30in both an assembled or disassembled condition.

At the upper end, each lift tube 62 is interconnected with a flowdeflector and impact assembly generally indicated by the referencenumeral 70. The deflector assembly includes a cylindrical outer shell 72and a centrally positioned coaxial lift tube extension 74 connected tothe upper end of the lift tube 62 by a coupling 76. Each lift tubeextension 74 is supported within its shell 72 by means of a plurality ofvertical rib members 78 extending radially outward from the lift tubeextension at right angles to one another as best shown in FIGS. 2 and 3.

Adjacent the upper' end, each lift tube extension 74 is formed with anannular end wall 80, which wall forms an outer portion of an impacttarget for the upwardly moving, fluidized particulate matter carried inthe lift tube 62. As best shown in FIG. 5 the end wall 80 is formed witha central aperture therein in order to accommodate the lower end of anelongated support rod 82 extending upwardly therethrough. As best shownin FIG. I, the support rods 82 project upwardly through openingsprovided in the circular wall 24 between the intermediate housingsection 22 and an upper housing section adjacent the level of the hopper16. At the lower end, each support rod is provided with a largecylindrical head 84, which head forms the central portion of an impacttarget for the upwardly moving fluidized particulate matter if the lifttube extension 74.

As best shown in FIG. 5, the upwardly flowing particulate matter forms apad of particulate matter in the upper end of the lift tube extensionand the pad of matter itself protects the structural members 80 and 84from excessive wear. The upwardly flowing matter impacts or strikes thepad of matter formed at the upper end of the lift tube and this causesfurther the oxidized coatings material to be knocked off of theindividual grains of the particulate matter. As shown by the arrows inFIG. 5, the material rebounds downwardly and is deflected outwardly bythe upwardly moving oncoming fluidized stream into a radially extendinghorizontal discharge tube 85 forming an elbow with the lift tubeextension and having an open outer end adapted to discharge the impactedmaterial which now includes relatively clean grains of particulatematter and the lighter in weight coating material which is knocked offor separated from base matter.

As best shown in FIG. 5, the outer, open ends of the discharge tubes 85are adjacent the outer surface of the cylindrical deflector shells 72.From the foregoing it will be seen that the individual granules ofparticulate matter flowing upwardly in the lift tube units are impactedagainst one another again and again. Moreover, repeated impacts occur asthe matter enters the lower inlet rings 64 on the lift tubes 62 as wellas during the upward flow in the tubes. Further impacts occur as thematter strikes the pad of material formed at the closed upper end of thelift tube extension 74. Moreover, a further impact zone is developedadjacent to the mouth of the discharge tube 85 where the downwardlyrebounding material collides with the upwardly moving matter before itmoves outwardly toward the outer end of the discharge tubes.

As best shown in FIGS. 1 and 2 when all four of the deflector assemblies70 of the respective lift tube scrubber units 30 are arranged with thedischarge tubes 85 directed radially inwardly toward the center of thehousing 12, an intense, impact scrubbing zone is formed in center of thehousing section 22. The heavier particles of material that aredischarged from the tubes in a horizontal direction as shown by thearrows A gravitate downwardly onto a conical structure 86 centered abovethe air plenum chamber 32. The sloping surfaces of the cone 86 directthe material outwardly toward the circular openings 28a in the wall 28and the material then flows downwardly into the shells 36 of therespective scrubber units 30 to be recycled in the scrubbing process.The impact scrubbing zone centered above the cone 86 may be formed bythe impingement of moving material streams impacting one another fromopposite directions as described and set forth in the foregoingcopending United States patent application, or in the alternative, aremovable target structure 88 may be provided. The target structureincludes pairs vertically extending impact vanes 90 which are securedalong their inner vertical edges to a central hollow tube 92. The tube92 is adapted to be restrained by upstanding support stud 94 which issecured to the apex of the cone 86. For lifting the target from the studa handle 96 is provided at the upper end of the tube 92.

As shown in FIGS. 1 and 2 when the discharge tubes 85 are directedradially inwardly the flow of material (arrows A) strikes the convergentsurfaces of the impact vane 90 and the collisions of particles with thevane surfaces causes another intense scrubbing zone to developimmediately above the cone 86. In this region additional coatingmaterials remaining on the grains are knocked off and removed by therepeated impacts. The heavier grains of particulate matter gravitatedownwardly onto the sloping surfaces of the cone 86, and are directedinto the shells 36 of the respective scrubber units 30 through theopenings 28a in the wall 28. In this manner the particulate matter beinghandled by the scrubber 10 is continuously recycled through theindividual lift tube scrubber units 30 for a selected period of timeuntil the desired degree of cleaning action is obtained.

Each individual deflector 70 is supported by a rod 82 and each rod isprovided with an enlarged head 84 at the lower end. The deflectors arerotatable from the normal operational position of FIG. 2 to thedischarge position of FIG. 3 wherein the discharge tubes 85 are directedradially outwardly away from the center of the housing 12. Each supportrod is keyed to its deflector for rotation therewith by a cross pin 98(FIG. 5) which extends through slots 74a provided on diametricallyopposite sides of the lift tube extension 74 at the upper end as shownin FIG. 5. When the support rods 82 are rotated from the position shownin FIG. 2, the discharge tubes 85 of the respective deflectors 70 willbe rotated a like amount to direct the discharge of material outwardlyas shown in FIG. 3 by the arrows A.

With the deflectors 70 positioned in the discharge position as shown inFIG. 3 the fluidized stream of particulate matter and coating materialsseparated therefrom are directed outwardly through the housing wall intoa plurality of separate discharge boxes secured to the outer surface ofthe housing 12 and referred to generally by the reference numeral 100.Each discharge box is positioned adjacent an elongated vertical slot 102formed in the wall of the scrubber housing 12 and aligned with theoutlet end of the discharge tubes 85 when the deflector assemblies 70are in the discharge position as shown in FIG. 3. As best shown in FIG.1, the slots 102 are longer in vertical dimension than the diameter ofthe discharge tubes 85 and the vertical adjustment of the lift tubesprovided to vary the distance D changes the level of the dischargingstreams issuing from the outlet ends of the discharge tubes 85 into therespective discharge boxes 100. The slots 102 are slightly larger inwidth or horizontal dimension than the outside diameter of the dischargetubes 85 so the precision alignment is not required when rotating thedeflector assemblies 70 into the discharge position as shown in FIG. 3.

Each of the discharge boxes 100 includes a pair of opposite side walls104, an outside wall 106, a top wall 108 and a bottom wall 1 l and theouter wall of the intermediate section 22 of the scrubber housing 12provides an inside wall for the discharge boxes. In order to protect theouter side walls 106 of the discharge boxes from excessive wear andabrasion from the discharging materials of the discharge tubes 85 andfurther to provide a secondary impact zone for separation of the lighterweight coating materials from the base particulate matter, eachdischarge box is provided with a relatively thick, heavy, hanging baffle112 formed of resilient material such as rubber and the like andextending downwardly through a slot formed in the top wall 108. Thebaffles hang freely and are positioned directly in front of thedischarging streams from the discharge tubes 85. Each hanging baffleincludes an enlarge bulbous upper end portion for supporting the bafflefrom the top wall of the discharge box and the lower end portion of thebaffle is free to swing and may be deflected by the high velocity streamof material impinging thereon. Within each discharge box 102 there isprovided a pair of adjustable baffles 1 14 and l 16 supported on shaftsrotatably controllable from the outside of the boxes to achieve desiredslopes for directing the heavier, cleaned sand grains or otherparticulate matter downwardly towards the lower end wall 110. A fixedbaffle 118 is also provided to guide the downwardly flowing material asit drops from the hanging resilient baffle 112 onto the adjustablebaffle 114. The material sifts downwardly in a falling stream or curtainfrom the lower edges of the baffles as it moves toward the lower end ofthe boxes. The thickness of the streams of material is controlled by theadjustable baffles. Material reaching the bottom wall 110 flows througha bottom discharge outlet 110a via a short pipe section 122 into theupper end of a pinch valve 120. The lower end of the pinch valves 120maybe interconnected to a common discharge manifold 124 so that thecleaned particulate matter from the scrubber may be discharged ortransported via a pneumatic transport system or the like such as thatshown in U.S. Pat. No. 3,297,366. The pinch valves 120 may be of thetype shown in this patent and are normally closed until a sufficientamount or head of material has been collected in the upper portion ofthe valve housing. The flexible sleeves then open to discharge thematerial into the pneumatic transport system. The valves may also bepositively controlled to open and close.

In order to separate the lighter in weight coating materials removedfrom the grains or base particles of the particulate matter beingtreated, each discharge box 100 is provided with an atmospheric damperassembly 122 which permits air to enter the lower end of the dischargebox through an opening 104a in one of the side walls spaced below thefixed baffle 118 as best shown in FIG. 1. Air entering through thedampers 122 passes upwardly in a tortuous path moving upwardly throughthe downwardly flowing curtain of material discharged from the loweredges of the respective baffles 1 14, 1 16 and 118. This upwardly movingdraft of air current carries the lighter weight materials upwardly todischarge outlets 128 formed on the upper walls 108. The dischargeoutlets 128 on the top walls 108 of the discharge boxes are connected toa suction manifold and a discharge fan 132 is provided to provide thenecessary draft for removal of the fine materials as shown in FIGS. 1, 2and 3. The amount of fines removed can be controlled by adjusting thenegative pressure in the discharge boxes. It will thus be seen that thebaffles 112 in discharge boxes 100 provide yet another impact Zone andthe air draft therein provides means for separating the cleaned sandgrains from the lighter weight coating materials that is knocked off ofbase particulate matter. The cleaned sand is collected in the lower endof the discharge boxes 100 for delivery by a suitable transport systemor the like to another location for further use.

In accordance with an important feature of the present invention, aspreviously described, the lift tube 62, ring 64 and deflector assembly70 of each individual scrubber unit 30 is supported by an individualelongated support rod 82 having an enlarged head 84 at the lower end.The rods project upwardly through openings 24:: in the circular wall 24(FIG. 5) into the upper portion of the housing adjacent the level of thehopper 16. Each support rod 82 is keyed to a lift tube extension 74 bymeans of a cross pin 98 so that rotation of a support rod will cause thedeflector assembly 70 to rotate therewith.. Rotation of all of thesupport rods 82 by 180 from the position of FIG. 2 causes the dischargeassemblies 70 to rotate in unison until the discharge tubes 85 aredirected outwardly in the discharge position as shown in FIG. 3. Inorder to limit and control the amount of rotation, of the dischargeassemblies 70 at least one shell 72 is provided with a pair ofupstanding limit stops 134 and 136 secured to the inside surface as bestshown in FIGS. 1, 2 and 3. In order to control the flow of sand or otherparticulate matter into the scrubber from the discharge opening 20 ofthe hopper 16, there is provided a conical valve member 138 adapted toopen and close the discharge opening to regulate the flow. The conicalvalve member 138 is mounted on the outer end of a cylinder rod 140a of avertically positioned, fluid operated valve cylinder 140. The lower endof the cylinder 140 is supported on a channel-like base 142 positionedin the intermediate housing section 22 and supported from the uppercircular wall 24 at opposite ends by depending brackets 144 as bestshown in FIG. 1. As shown in FIGS. 2 and 3, opposite side edges of thesupport channel structure 142 cooperate with the upstanding limit stops134 and 136 on the right hand (FIG. 1) deflector assembly 70 to providefor alignment of the discharge tubes 85 of the respective deflectorassembly in the normal operating position (FIG. 2) or the dischargeposition (FIG. 3).

Referring now more particularly to FIG. 5, the support rods 82 of therespective deflectors 70 are connected by turnbuckles 83 with upper ends87 which extend upwardly through the openings 24a in the circular wall24. The upper end portion of each upper rod is slidably disposed in apair of flanged bearings 146 spaced on opposite sides of a chainsprocket 148, which is secured by set screws 150 to a sleeve 151attached to the support rods 87 by a removable pin 153.

The lower flanged bearing 146 is attached to the upper surface of thecircular wall 24 and the upper flanged bearing is attached to the uppersurface of acircular support plate 152 supported in parallel, spacedapart relation above the circular wall 24 by a plurality of support postassemblies 154. An endless roller chain 156 is entrained around all ofthe several sprockets 148 in order to drivingly rotate all of thesupport shafts 82 in unison and thereby rotate all of the deflectorassemblies 70 when it is desired to move the deflectors from a dischargeto an operating position or vice versa.

As shown in FIG. 4, the roller chain 156 is passed around all of thesprockets 148 of the respective support rods 82 and in addition, thechain is passed around a pair of idler sprockets 156 into drivingengagement with a single drive sprocket on the output shaft of a fluidmotor 160. The fluid motor 160 is reversible and is supplied from asource of compressed fluid. A valve system is used to operate the motorin reverse directions in order to rotate the deflector assemblies 70back and forth between the normal operating position and the dischargeposition of FIGS. 2 and 3. Normally the fluid motor is actuated torotate the sprocket 158 in a given direction for a selected timeinterval, which interval is slightly longer than the time required torotate the deflector assemblies through 180 from one position to theother. Rotation of the deflectors is stopped by engagement of one or theother stop members 134 or 136 with the side of the support channel 142as previously described.

When it is desired to adjust the spacing distance D between the upperend of the nozzle 42 and itsrespective entrance ring 64 on the lift tube62, the set screw 150 on the sprocket 148 is loosened and the supportrod is moved up or down as desired to provide the proper spacing D.After the spacing is set the set'screw 150 is retightened to again keythe sprocket to the support rod.

The scrubber provides means for adjusting the individual clearancedistance D between the lift tube entrance ring and the nozzle in each ofthe scrubber units 30 and in addition the system provides forsimultaneously rotating all of the deflector assemblies 70 of therespective scrubber units to the normal operating or the dischargeposition as desired.

As shown in FIG. 1, relatively large access slots 162 are provided inthe housing wall 12 so that the chain, sprockets, bearings and setscrews may be serviced and adjusted as described. In addition, as shownin FIGS. 2 and 3 the intermediate section 22 of the housing 12 is formedwith relatively large access openings 164 in the side wall in order topermit servicing or replacement of the individual deflector assemblies70. These may be removed completely from the housing 12 by detachmentfrom the respective lift tubes 62 when the couplings 76 and the setscrews 150 are loosened. The access openings 162 are large enough inwidth and height to permit easy service or complete withdrawal of adeflector assembly 70. During normal operation, arcuate cover plates 164are provided to cover the access openings 162 and confine theparticulate material and dust within the intermediate section 22 of thehousing 12.

Although the present invention has been described with reference to asingle illustrative embodiment thereof, it should be understood thatnumerous other modifications and embodiments can be devised bythose-skilled in the art that will fall within the spiritand scope ofthe. principles of this invention.

I Whatis claimed as new and desired tobe secured by Letters Patent-ofthe United States is:

' 1. Animpact scrubber for removing-coating materials from the surfacesof particulate. matter such. as foundry sand and' the like comprises atleast one lift tube unit having a lift tube with an inlet end and anopposite end for containing a high velocity fluidized stream of saidmatter; fluid injector means spaced adjacent said inlet end for carryingsaid particulate matter into said inlet end and forming a fluidizedstream of said matter in said lift tube, fluid stream deflector meansadjacentand in communication with said opposite end of said lift tube,means mounting said deflector means for rotation around a longitudinalaxis of said lift tube, said'deflector means including a discharge tubefor directing said fluidized matter in-a single stream angularly outwardwith respect to said longitudinal axis of said lift tube at differentrotative positions,and means for rotating said deflector means fordirecting said discharge tube in a selected one of a pluralityofrelative rotative positions.

2. The scrubber of claim 1 including means for supporting said lift tubein a selected one of a plurality of different axial positions relativeto said injector means wherein said spacing between -said inlet end andsaid injector'means may be selectively adjusted. I

3. The scrubber of claim 1 including a plurality of said lift tubeunits, a common housing for said'units having a central axis spacedbetween said units, said means for rotating said deflector 'rneansoperable-to position a discharge tube for each lift tube in a selecteddirection facing toward said central axis oraway from said axis, andseparator means including enclosures spaced on opposite sides of saidhousing for receiving fluidized streams of material discharged from saiddeflector means when positioned to discharge away from said centralaxis, said separator means further including means for separating saidparticulate matter and said coating materials removed from the surfacesof said particulate matter.

4. The scrubber of claim 3 wherein said supporting means includes meansfor supporting each of said lift tubes in selectively adjustable axialpositions relative to their respective injector means wherein saidspacing between said inlet end and said injector means of each unit maybe varied.

5. The scrubber of claim 3 wherein said deflector means of each unitincludes a lift tube extension having a closed upper end and a dischargetube angularly extended outwardly from said lift tube extension and incommunication therewith at a level below said closed end.

6. The scrubber of claim 5 wherein each unit includes removable couplingmeans for interconnecting a lower end of said lift tube extension andsaid opposite end of said lift tube.

7. The scrubber of claim 5 wherein said housing includes dischargeopenings formed on opposite sides in communication between saiddischarge tubes and said separator enclosures when said deflector meansare rotated to discharge in opposite directions away from said centralaxis.

8. In an impact scrubber for removing coating materials from thesurfaces of particulate matter such as foundry sand and the like, anenclosure, flexible target means in said enclosure, inlet means adjacentan upper level of said enclosure for directing a flow of said matter andmaterial against said target means, said target means including a pieceof flexible material supported from an upper end portion to hanggenerally vertically in said enclosure with a freely deflectable lowerend portion spaced in front of said inlet meaans, baffle means in saidenclosure below said inlet means for forming a curtain of downwardlyflowing matter and material and draft means for moving a flow of airthrough said curtain for carrying at least a portion of said coatingmaterials upwardly away from said particulate matter.

9. The appartus of claim 8 wherein said draft means includes an airinlet opening in said enclosure spaced below said baffle means andsuction means in communication with said enclosure above said bafflemeans for inducing air pass into said air inlet opening and through saidcurtain of material flowing downwardly of said baffle means.

10. The apparatus of claim 8 wherein said baffle means includes at leastone sloped baffle and means for adjustably selecting the angle of slopethereof.

11. An impact scrubber for removing coating materials from the surfacesof particulate matter such as foundry sand and the like comprises atleast one lift tube unit having a lift tube with an inlet end and anopposite end for containing a high velocity fluidized stream of saidmatter, fluid injector means spaced adja cent said inlet end forcarrying said particulate matter into said inlet end and forming afluidized stream of said matter in said left tube, deflector meansadjacent and in communication with said opposite end for directing saidfluidized stream angularly outward with respect to a longitudinal axisof said lift tube for discharge therefrom, support means for rotativelysupporting said deflector means for directing said discharge therefromin a selected one of a plurality of relative rotative positions, andmeans for separating said coating materials and particulate matterincluding an enclosure for receiving said fluidized stream from saiddeflector means, flexible target means in said enclosure, inlet meansadjacent an upper level of said enclosure for directing a flow of saidmatter and material against said target means, baffle means in saidenclosure below said inlet means for forming a curtain of downwardlyflowing matter and material and draft means for moving a flow of airthrough said curtain for carrying at least a portion of said coatingmaterials upwardly away from said particulate matter.

12. The apparatus of claim 1 1 wherein said enclosure includes a sidewall, said inlet means adapted to direct a horizontal flow of materialthrough said side wall, and said target means comprises a piece offlexible material supported from an upper end portion to hang generallyvertically in said enclosure with a freely deflectable lower end portionspaced in front of said inlet means.

13. The apparatus of claim 11 wherein said draft means includes an airinlet opening in said enclosure spaced below said baffle means andsuction means in communication with said enclosure above said bafflemeans for inducing air pass into said air inlet opening and through saidcurtain of material flowing downwardly of said baffle means.

14. The apparatus of claim 11 wherein said baffle means includes atleast one sloped baffle and means for adjustably selecting the angle ofslope thereof.

1. An impact scrubber for removing coating materials from the surfacesof particulate matter such as foundry sand and the like comprises atleast one lift tube unit having a lift tube with an inlet end and anopposite end for containing a high velocity fluidized stream of saidmatter, fluid injector means spaced adjacent said inlet end for carryingsaid particulate matter into said inlet end and forming a fluidizedstream of said matter in said lift tube, fluid stream deflector meansadjacent and in communication with said opposite end of said lift tube,means mounting said deflector means for rotation around a longitudinalaxis of said lift tube, said deflector means including a discharge tubefor directing said fluidized matter in a single stream angularly outwardwith respect to said longitudinal axis of said lift tube at differentrotative positions, and means for rotating said deflector means fordirecting said discharge tube in a selected one of a plurality ofrelative rotative positions.
 2. The scrubber of claim 1 including meansfor supporting said lift tube in a selected one of a plurality ofdifferent axial positions relative to said injector means wherein saidspacing between said inlet end and said injector means may beselectively adjusted.
 3. The scrubber of claim 1 including a pluralityof said lift tube units, a common housing for said units having acentral axis spaced between said units, said means for rotating saiddeflector means operable to position a discharge tube for each lift tubein a selected direction facing toward said central axis or away fromsaid axis, and separator means including enclosures spaced on oppositesides of said housing for receiving fluidized streams of materialdischarged from said deflector means when positioned to discharge awayfrom said central axis, said separator means further including means forseparating said particulate matter and said coating materials removedfrom the surfaces of said particulate matter.
 4. The scrubber of claim 3wherein said supporting means includes means for supporting each of saidlift tubes in selectively adjustable axial positions relative to theirrespective injector means wherein said spacing between said inlet endand said injector means of each unit may be varied.
 5. The scrubber ofclaim 3 wherein said deflector means of each unit includes a lift tubeextension having a closed upper end and a discharge tube angularlyextended outwardly from said lifT tube extension and in communicationtherewith at a level below said closed end.
 6. The scrubber of claim 5wherein each unit includes removable coupling means for interconnectinga lower end of said lift tube extension and said opposite end of saidlift tube.
 7. The scrubber of claim 5 wherein said housing includesdischarge openings formed on opposite sides in communication betweensaid discharge tubes and said separator enclosures when said deflectormeans are rotated to discharge in opposite directions away from saidcentral axis.
 8. In an impact scrubber for removing coating materialsfrom the surfaces of particulate matter such as foundry sand and thelike, an enclosure, flexible target means in said enclosure, inlet meansadjacent an upper level of said enclosure for directing a flow of saidmatter and material against said target means, said target meansincluding a piece of flexible material supported from an upper endportion to hang generally vertically in said enclosure with a freelydeflectable lower end portion spaced in front of said inlet meaans,baffle means in said enclosure below said inlet means for forming acurtain of downwardly flowing matter and material and draft means formoving a flow of air through said curtain for carrying at least aportion of said coating materials upwardly away from said particulatematter.
 9. The appartus of claim 8 wherein said draft means includes anair inlet opening in said enclosure spaced below said baffle means andsuction means in communication with said enclosure above said bafflemeans for inducing air pass into said air inlet opening and through saidcurtain of material flowing downwardly of said baffle means.
 10. Theapparatus of claim 8 wherein said baffle means includes at least onesloped baffle and means for adjustably selecting the angle of slopethereof.
 11. An impact scrubber for removing coating materials from thesurfaces of particulate matter such as foundry sand and the likecomprises at least one lift tube unit having a lift tube with an inletend and an opposite end for containing a high velocity fluidized streamof said matter, fluid injector means spaced adjacent said inlet end forcarrying said particulate matter into said inlet end and forming afluidized stream of said matter in said left tube, deflector meansadjacent and in communication with said opposite end for directing saidfluidized stream angularly outward with respect to a longitudinal axisof said lift tube for discharge therefrom, support means for rotativelysupporting said deflector means for directing said discharge therefromin a selected one of a plurality of relative rotative positions, andmeans for separating said coating materials and particulate matterincluding an enclosure for receiving said fluidized stream from saiddeflector means, flexible target means in said enclosure, inlet meansadjacent an upper level of said enclosure for directing a flow of saidmatter and material against said target means, baffle means in saidenclosure below said inlet means for forming a curtain of downwardlyflowing matter and material and draft means for moving a flow of airthrough said curtain for carrying at least a portion of said coatingmaterials upwardly away from said particulate matter.
 12. The apparatusof claim 11 wherein said enclosure includes a side wall, said inletmeans adapted to direct a horizontal flow of material through said sidewall, and said target means comprises a piece of flexible materialsupported from an upper end portion to hang generally vertically in saidenclosure with a freely deflectable lower end portion spaced in front ofsaid inlet means.
 13. The apparatus of claim 11 wherein said draft meansincludes an air inlet opening in said enclosure spaced below said bafflemeans and suction means in communication with said enclosure above saidbaffle means for inducing air pass into said air inlet opening andthrough said curtain of material flowing downwardly of sAid bafflemeans.
 14. The apparatus of claim 11 wherein said baffle means includesat least one sloped baffle and means for adjustably selecting the angleof slope thereof.